1. Field of the Invention
The present invention relates to developing devices, image forming apparatuses, image forming systems, and methods of manufacturing developing devices.
2. Description of the Related Art
(1) There are developing device that are provided with: a developer containing section for containing a developer; a developing roller for bearing the developer contained in the developer containing section; and a roller-supporting member for rotatably supporting the developing roller.
In such a developing device, the coefficient of thermal expansion of the developer containing section differs from the coefficient of thermal expansion of the roller-supporting member. Therefore, there is a difference in the amount of expansion/contraction due to a change in temperature between the developer containing section and the roller-supporting member. In view of this, the developing device is provided with a gap for preventing the roller-supporting member and the developer containing section from interfering with one another when the roller-supporting member and the developer containing section expand/contract due to a change in temperature, which is caused by the difference in the coefficient of thermal expansion between the developer containing section and the roller-supporting member. This gap is designed to have a predetermined size, taking into consideration the amount of expansion/contraction of the roller-supporting member and the developer containing section due to a change in temperature. (See, for example, JP 2003-270928A.)
However, if the roller-supporting member is formed, for example, by connecting two members, then there are cases in which the roller-supporting member is not formed in the desired size due to variations in size of those members caused by individual differences. If the roller-supporting member is formed larger than the desired size, then the developer containing section and the roller-supporting member may expand/contract and interfere with one another due to a change in temperature.
(2) Another type of developing device is provided with: a developing roller for bearing a developer; a roller-supporting member for rotatably supporting the developing roller; and a roller gear that is provided at one end of the developing roller and that is for rotating the developing roller. In such a developing device, an intermediate gear is used for transmitting a drive force from a drive source to the roller gear, and the intermediate gear is supported by a gear-supporting shaft. (See, for example, JP 2003-270928A.)
In this type of developing device, the roller-supporting member may be structured by connecting at least two members in order to support the developing roller, and screws are often used to connect these members.
In assembling such a roller-supporting member, there has been a demand for improvement in the ease of assembling the roller-supporting member from the standpoint of, for example, shortening the time required for assembly.
(3) Further, image forming apparatuses such as laser beam printers are well known in the art. Such image forming apparatuses are provided with, for example, an image bearing body for bearing a latent image, and a developing device that develops the latent image borne on the image bearing body with a developer. When the image forming apparatus receives image signals etc. from an external device such as a host computer, the developing device is positioned in a developing position which is in opposition to the image bearing body, the latent image borne on the image bearing body is developed with the developer contained in the developing device to form a developer image, the developer image is transferred onto a medium, and ultimately an image is formed on the medium.
The developing device of the type described above has, for example, a developer charging member for charging the developer borne by a developer bearing roller, a bearing-roller-supporting member that is made of metal and that is for rotatably supporting the developer bearing roller, and a charge-supporting member that is made of metal and that is for supporting the developer charging member. (See, for example, JP 2003-270928A.)
In this type of developing device, it is necessary to arrange the developer charging member in an appropriate position with respect to the developer bearing roller so as to electrically charge the developer borne by the developer bearing roller evenly. In order to arrange the developer charging member in an appropriate position with respect to the developer bearing roller, it is necessary to arrange the charge-supporting member, which supports the developer charging member, in a suitable position with respect to the bearing-roller-supporting member, which supports the developer bearing roller.
Usually, the bearing-roller-supporting member and the charge-supporting member are fastened to one another with screws. However, if the bearing-roller-supporting member and the charge-supporting member are fastened to one another with screws, then the position of the charge-supporting member with respect to the bearing-roller-supporting member may deviate from its proper position due to the turning force etc. applied to make the screw turn during fastening. In this case, the position of the developer charging member with respect to the developer bearing roller may also deviate.